Method for obtaining hydrocarbons of low boiling points from hydrocarbons of high boiling points



1,742,165 NG POINTS P. DANCKWARDT 13 LOW BOILI FROM HYDROCARBONS OF HIGHBOILING POINTS Filed April 25, 1927 METHOD FOR OBTAINING HYDROCARBONS ODec. 31, 1929.

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This invention relates to a process, for producing from fixedhydrocarbon gases and such hydrocarbons of high boiling points, as forinstance fuel oil or tar, hydrocarbons p of low boiling points,identical with or simi lar'to gasoline. lit is known as a fact thathydrogen can be added to or combined with certain hydrocarbons by theapplication of high pressure and high temperature, but as n this isusually carried out by an apparatus in which firecomes into directcontact with the oil container, a great deal of carbon is formed by theintense heat and this, in conjunction with the high pressure required,has s prevented this process from becoming of commercial value to theoil industry. T have, therefore, discarded direct heat by combustionaltogether andattain the desired conditions in an altogether novel ndperfectly as practical way. I r

The invention, briefly described, consists in producing the requiredtemperature and pres sure in a mechanical way by compressing the fixedas andaipart of the oil vapor to a high egree, this compression totalre'place within the body of oil, and separating the light'hydrocarbonsformed from the oil by fractional distillation. Though there is alwaysunder these conditions a certain amount of free hydrogen formed besideslight hydrocarbons, escaping from'the condensing apparatus, it isnaturally desirable to have an excess of free hydrogen inorder toproduce a more favorable chemical equilibrium be- 1 of the accompanyingdrawing represents a longitudinal section of the apparatus which Iemploy for carrying out the 50 process; and

tween the products entering into reaction with each other -in the stilL-Therefore, it is Figure 2 shows a detail of a modified con struction.

The still consists of a steel shell l-l-1--'--il of cylindricalcross-section which is well in sulated by an outside covering ofasbestos 22-%2, which reduces the loss of heat by conduction to aminimum. At one end a manhole 3 is provided, and valved pipes 4t and 5serve as inlet and outlet of oil. A pipe 6 connects the'still with anair-cooled con desner 7, fromwhich the uncondensed light hydrocarbonsare transferred by means of the valvedpipe l to a water-cooled condenser9, The products are then discharged into a-closed vessel 10, from whichthe fixed gases may be allowed to escape into the air through valve 31,or they may be conveyed through a pipe 11 and the short branch pipe 32baclr into the system, or they may be made to pass first through aheater 28, containing red hotcarbon by closing valve 32 and openingvalves 3d and 37," and then baclr to the still, as may be'required atthe diderent phases of the operation of the process Two valves 33 and3dare provided in pipe it for the purpose of controlling the flow ofgases' lln the interior of the still l--l--l-l there are placed one ormore compressors l3l3-l3 arranged above and resting on cross bars M ttitwhich are riveted to the shell of the still, These compressors may allbe driven by the same crankshaft 15--l5, The journals ld--ltt-lli-ltsupflit (lift fit) port the shaft inside of the still. flnthe outsidethere is another journal If, and near, it is placed the flywheel 18. Theshaft is then coupled to the prime mover 19, which may be a gas, oil orsteam engine. it stud ing box 20 is provided with a branch at,

through which cold oil may be introduced a to keep the intense heat awayfrom the packing. llf more than one compressor is used, which is thebest plan where high pressure is desired, the cylinders areroportionately reduced in diameter, and 'te compression products fromthe first one on the left pass serially to the central one, and fromthis to the right hand one through pipes E222 and 23, and are thenforced intoa longclosed coil 24--% which is provided at its. enthe tremeend with an automatic pressure valve that will open at a certainpressure of the gas slightly below that of the pressure when the gasleaves the last cylinder. This coil thus serves as a reservoir for thecompression products and holds them unt1l they have surrendered theircompression heat to the surrounding body of oil. Besides this itregulates the escape of the products into the oil without sudden shock.The intake 25 to the left. hand compressor has two branches 26 and 27.Both pass outside through the shell of the still and each branchisprovided with a valve located outside of the still. Pi e 26 is,however, bent back and its open end connects with the vapor space abovethe oil level inside of the still. The otherpipe 27 connects thecompressor with the top of the producer 28. The compressor, therefore,can draw ases .from the producer or vapors fromthe interior of thestill, or from both places-at the same time and in any desiredproportion vaccording to the setting of the valves. v v

The producer is provided near its bottom with a valved air supply pipe29 and a valved outlet pipe .30, these valves being opened only when airis passed through the interior for heating the carbon (coke contained init, which must be done whenever the temperature of the coke falls toolow for decomposing the fixedhydrocarbon gas.

At such times the valve of pipe 27 must be closed in order to allow thecombustion es to escape only through. pipe 30.

and pipe 11. The 'light hydrocarbons formed-by the process are.collected in the receiving tank 10 and may be withdrawn from it througha valve 35.

I will now proceed describing the operation of the rocess in detail, asit may be carried out in the above apparatus.

We will suppose that the producer 28 is to be used to supply plenty ofhydrogen in the free state, as it assists greatly in roducing thelargest ossible amount of light hydrocarbons. Be ore igniting the fuel,however, itis necessary to expel all the air from the still, asotherwise, when hot bydrogen-is introduced, an explosion or at least aviolent combustion might ensue. The

still is therefore first filled with oil, which may be preheated, up toa level just below the opening of pipe 26, and with the valves indpiples 26, 27 and the valves 33, 34 shut an t e valves in pipes 812 andvalves 31 and 32 0 en. I now; start the engine 19. Hydrocar 11 gasis-admitted through the pipe 12 from an outside source (not shown), thecompressor suckin it through the cross line and valve 32 and dischargingit into the oil through the valve in the end of pipe 24, from where itrises to the space above the ere is also a branch line with a valve 32'for forming a short cut between pipe 27 oil, driving all the airgradually out of the whole system through valve 31. I then close valve31 and open 33 and continue the operation of the compressors, which nowcirculates the hydrocarbons contained throughout the whole apparatus,and the compression heat gradually raises the temperature of the oil toits boiling point, whereafter valve 26 maybe opened and so re ulatedthat the compressors take in, beside's fixed hydrocarbon gas, a certainamount of va or from the space above the boiling oil. lihder theinfluence of the high pressure and the high temperature within thecompressor cylinders and the coil, the vapors of the heavy oil arecracked inside of the cylinders and coil. and recombine with a part ofthe hydrocarbon gases and hydrogen to form hydrocarbons of lower boilingpoints, which will escape as vapor into the condensers, the last one ofwhich condenses the lightest part of them, the aircooled condenserseparating out some heavier hydrocarbons which will flow back throughpipe 6 into the still.

In the meanwhile the charge of the producer may have been ignited and itis oper+ ating as a producer generally is, the air being blown in at 29and the combustion gases escaping from 30. When the charge of coke ishot enough, this process is interrupted by closing the valves inpipes-29 and 30. I

then open the valve 34 and the valve in pipe 37 and close the valve 32,whereby the current of fixed gas is changed so that it traverses theproducer before entering the compressors. The valve in pipe 12 remainsopen so that always some fresh fixed hydrocarbon gas may be drawn in bythe compressors whenever needed. The fixed hydrocarbons incoming now incontact with the red hot carbon in the producer are broken up formingmostly carbon and hydro en which latter in being compressed with t evapors comin through 26 form with them the desirable ydrocarbons of lowboiling points, and this more readily than the undecomposed fixedhydrocarbons do. Working in this way the heavy oil surrounding-thecompressors and the coil is not submitted to extreme temperatures as ina firP--'.'-ated still, which would cause it to decum p use into carbonand fixed gas, but only such part as is drawn into the cylinders ishighly heated, but very uniformly without beingexposed to red hot spotsas happens' alwaysin a fire-heated still or coil, apd as it i's-in,contact with an excess of free'hydrogen under a high pressure it findsthe conditions most favorable for the formation of saturatedhydrocarbons of low-boiling points. By the proper manipulation of, thevalve 26, the proportion of oil vapor and fixed gas can be easilyadjusted so as to yield the best rether more vapor would be admitted tothe ture of the oil surrounding the compressors andcoil will be highenough when it vis just boiling at atmospheric pressure without drawingheat too fast from the interior of the compress0rs.- Should,nevertheless, a higher temperature of the oil surrounding thecompressors be found to be desirable, when working for instance withlighter oils as raw material, this caneasily be obtained by closing thevalve in pipe 12 entirely and partly closing the valve in pipe 8, whichwill immediately put the whole interior of the still under pressure andconsequently cause the boiling point of the oil in the still to riseinproportion to the rise of the pressure.

Whenever the temperature in the producer has fallen so low thatsuflicient hydrogen is not formed, the gas current is switched so as totake the course via the cross line through valve 32 and all the othervalves must be setagain so as to allow a reheating of the contents ofthe producer. As this procedure necessitates an interruption in thesupply of fixed gas carrying a large percentage of hydrogen, it will bebetter to have two pro-- ducers, one running on the reheating phasewhile the other one is receiving the current of fixed gas fordecomposition (not shown). Or, when working on a very large scale, the

producer plant for treating the fixed hydrocarbons ma be made altogetherindependent of the distil ing apparatus, and the latter may receive theprepared fixed hydrocarbons from a storage tank.

Though this process will produce the desired-light hydrocanbons by theuse of pressures ranging between 100 and 200 pounds per square" inch,the reaction is greatly accelerated when the process is carried on at apressure between one thousand and three thousand pounds. The use of suchpressures in a common pipe or pressure still heated by direct fire isimpracticable and dangerous, but perfectly practicable and safe whenperformed in the above described way. It must be understood, however,that with very high pressures care must be taken to see that the-heatcreated internally is rapidly removed and transferred to the oilsurrounding the compressors. This can be effected either by the use of alarger number of compressors, so that compression will take place inmore stages, by providing the compressors with cooling ribs, or byreplacing the straight short pipes connectingone compressor with thenextone by long coiled pipes, sothat the temperature diiference between theinterior of each compressor and the surrounding oil 1 taneously incontact with the oil surrounding the compressors. W

Should it be found to be desirable to know at any time the temperatureat which the vapors escape from the last compressor,the pipe leadingfrom it may be extended through the shell of the still and bent backinto the interior again, the outside bend being provided with an openingX for the insertion of a pyrometer P, as shown in detail in Fig.2. Thissame figure also shows the automatic discharge valve in the end of pipe24 replaced by a hand operated valve-Y, placed in an outside extensionof the coil line, and so arranged that the contents of the coil aredischarged back into the still. While not absolutely necessar thesemodifications will assist in the COIltI'OlYOfithfl process.

Having thus described my invention what I claim as newis: v

1. In the heating of oilby an apparatus comprising a still adaptedtocontain a body of oil and a plurality of compressors connected in seriesand located within the oil, a process which consistsin compressing fixedhydrogen containing gas and oil va ors in successive stages to such apressure t at the oil within the still will boil. 2. In the heating ofoil by an apparatus comprising a still adapted to contain a body of oiland a plurality of com ressorsconnected in series and located wit inthe'oil, a process which consists in compressingfixed ydrogencontainingfgas and oil va ors in successive stages to such a pressure tat the oil within the still willboil, and transferring heat from thecompressed products to the oil.

3. The process of producing hydrocarbons of low boiling points fromhydro en con taining gas and hydrocarbons of high boilingp'oints bymeans of an apparatus comprising a closed still containing a body of oiland a plurality of compressors connected in series and located withinthe oil, which consists in mixin some of the vapors from the heated oilwit 1 hydrogen containing as and compressing the mixture within the odyof oil to a pressure of over two thousand pounds per square inch,permitting the compressed gases and vapors to escape into the oil at apressure not less than two thousand pounds per square inch, withdrawingvapors and gases, separating the high boiling from the low boiling vaors and from the gases, separating the low iling va ors from the gasesby condensation of the ormer, mixing the gases with hydrogen andreturning the gaseous mixture to the com ressors.

4. The process of pro ucin hydrocarbons of low boiling points fromiydrogen con taining gas and hydrocarbons of h gh boiling points bymeans of an apparatuscomprism ing a closed still containing a body ofboiling oi and a plurality of compressors connecte in series and locatedwithin theoil and a gas enerator comprising a body of glowingcaronaceous material, whichconsists in passing fixed hydrocarbon gasthrough the glowing l5 carbonaceous materlals whereby free hydrogen gasis formed, mixing a part of the vapors formed by the boiling f. oil withthe mlxed hydrocarbon gas and hydrogen, subjecting the mixture thusformed to a pressure of over a two thousand pounds er square inchwhereby hfydrocarbons simi ar to natural gasoline are armed, withdrawingvapors and gases separating the hi h boiling from the low v u bOlllIlgvapors an from the gases, separating the low boiling vapors from thegases by condensation of the former and returning the gases into the gasgenerator;

5. The method of producing hydrocarbons of low boiling points fromhydrocarbons of high boiling points b means comprising a 1 gas generatoradapte to contain a body of giowin carbon, a still adapted to contalii ady 0 liquid hydrocarbons of highboilin point and-a multistage compressorlocated within the still and within the body of liquid hydrocarbonswhich consists in heating the liquid hydrocarbons to such a temperaturethatthey will give off vapors and gases, ad-

mitting hydrogen into the vapor space above the liquid hydrocarbons sothat a mixture of hydrogen and {hydrocarbon vapors and gases is formed,continuously withdrawing a' portion of the gaseous mixture andcompressing a it to such a pressure that-the heat generate will raisethe liquid hydrocarbons to a temperature above boiling, discharging thecom- 1ressed gaseous mixture into the body of iquid hydrocarbons wherebythe heat will 6 be more effectively transferred to the liquidhydrocarbons, conductin .va ors and ases from the space above the iquihydrocar ons to a condenser, separating the condensates from the .fixedgases and then passing the ases through the gas generator whereby freeydrogen is produced. In testimony whereof I aflix my si ature.

PAUL DANCKWA DT.

